Utility vehicles such as golf carts require small braking assemblies that provide adequate braking power with minimal input force. One such method for providing such a braking force is through the use of caliper disc braking assemblies that use ball ramp actuators. Typically, a ball ramp actuated brake includes several metal balls, sandwiched between a ramp plate and a stationary plate. The ramp and stationary plate include ramped depressions within which the balls reside. The balls are located in a circular pattern about a central pivot axis. If braking torque is desired, the operator causes the ramp plate to rotate about that axis, which moves the balls along the depression thus forcing the two plates apart. This force is transferred to a pair of brake pads on both sides of a rotating disc, causing them to apply pressure to the rotating disc which in turn creates brake torque.
Prior art ball ramp actuated brakes have numerous drawbacks. The bridge across the caliper that transfers the braking force to the brake pad is typically not at the geometric center of the braking force generated by the ball ramps. This causes a bending moment when braking force is applied. Because of the bending moment, the braking assembly must be much stronger and larger than would ordinarily be necessary. Also, the bending moment causes uneven wear of the pads and results in a lack in efficiency. In addition, not having the bridge at the geometric center of the braking force limits the methods of manufacture of the bridge. Additionally, the ramp and stationary plates of prior art ball ramp actuated brake assemblies are typically machined. This method of manufacturing is required because the ramp surface opposing the ball depressions must be flat in order to effectively transmit the braking force. This requirement eliminates the availability of less expensive manufacturing methods such as stamping or pressing.
In view of these problems, it is evident that the need exists for a ball ramp actuated braking assembly which provides greater efficiency, reduced bending moment, improved pad wear, all at a reduced manufacturing cost.